This trick works perfectly with the FilmAffinity or TheMovieDB add-on because of the setting "Scan Recursively". I've used it for grouping content in different disks for the same category (Documentaries, Movies, Movies VO, etc.) without having to create 'n' entries of content.

The problem with TheTVDB is that it doesn't scan recursively so it only founds the junctions (T and U folders) and try to scrappe the information (I get "Mister T" and "True U" as the series ;-).